Weighing systems have existed that weigh pieces and combine the pieces into a package having a predetermined weight. These current weighing systems use a manual method or a “deli” weight method. The manual method requires people picking through a pile of pieces, choosing potential pieces that look and feel like they might combine to achieve the target weight and if not, then the process of substituting pieces begins until weight falls within a fixed weight tolerance. The current weighing systems have a number of problems. For example, the manual process is labor intensive, costly, inefficient and results in large variances in final weights.
The deli weight method can be done manually or automatically with a machine, but due to the inaccuracy of the process, a volumetric approach is used to estimate the weight and the final weight may not fall between upper and lower limits. The deli method has its own problems. Specifically, the deli weight method does not have the required precision and often more than the desired target weight limit is put into packages resulting in lost profit.
Some other problems with current solutions are that they are manual in nature, highly inefficient, highly inaccurate and prone to damaging pieces. This can result in high cost, reduced profits, lower quality product shipped to market, brand tarnishing and other problems.
An additional conventional method is to use an automated multihead weigher system. This system uses conveying apparatus which load vibratory dispersion devices. Material is then dispersed into multihead weighers or buckets with weighing capability. Challenges are numerous with these type systems for some products. For instance, some products interlock to form larger pieces that exceed the target weight and thus must be recycled and reworked. The product being weighed can also be abused during conveying, vibration and dropping which have a negative effect due to loss in valuable residue which reduces efficacy or increases particulates which can stick to system surfaces. Finally, the low number of piece weight options available to combine and achieve lower and upper weight control limits is inefficient.